Psychologists define the 'dark core of personality'

Egoism, Machiavellianism, narcissism, psychopathy, sadism, spitefulness are all traits that stand for the malevolent dark sides of human personality. Results from a recent project show, these traits share a common 'dark core.' So, if you have one of these tendencies, you are also likely to have one or more of the others.

from Health & Medicine News -- ScienceDaily https://ift.tt/2OZjPpi